A major project of this section is the development of new statistical genetics methodology as prompted by the needs of our applied studies. This year Dr. Bailey-Wilson worked on development of several new methods. The first, in collaboration with Dr. Silvano Presciuttina from the University of Pisa, is the development of a stepwise procedure for using a few genetic markers at each step to try to differentiate siblings from unrelated individuals. This methodology has applications in linkage analysis and in forensics. A new version of this method using likelihood methods has been developed this year and a a manuscript is in preparation. The second project, also in collaboration with Dr. Presciuttini, is a method to examine haplotype sharing of transmitted versus non-transmitted chromosomes in a sliding process down a human marker map. This method was presented at the 2001 International Congress of Human Genetics and a manuscript is being prepared for publication. The third project, in collaboration with Dr. Jim Malley at CIT, NIH, is the development of a new method for family based association tests that appears considerably more powerful than the TDT but more robust to false positives than is case-control association. Extensive simulation studies have been performed to test the performance of this method. A paper demonstrating the properties of this method on simulated data was recently published in Genetic Epidemiology and another paper is in preparation. The fourth project, also in collaboration with Dr. Malley, is application of less conservative methods of correcting for multiple testing in human genetics analysis. The results of some of this work was recently presented at the 2001 meeting of the International Society for Genetic Epidemiology and a manuscript is in preparation. Finally, work is being done in this section to improve upon the computer implementation of various existing analysis methods. These projects are ongoing.